In providing accurate mixture proportioning and dispensing the gun is molded of plastic to assure exact proportioning dimesions, and is light enough to minimize fatigue in its use. The parts are preferably molded inexpensively of light materials such as high impact plastics which provide and maintain consistent performance accurate under temperature changes. However, these materials and parts are vulnerable to hard impacts, and damage, when connected to supply hoses and dropped onto the floor from above the waist level of the user.
If solute is supplied by a plastic bottle type container carried by the gun, the container can break the force of a fall, but where a solvent hose and one or more solute supply hoses are connected to a hand carried gun, such elimates the use of solute containers, but the weight of the supply hoses with liquids in them, particularly when touching the ground at a point remote from the gun will dominate its free falling movement, under gravity, in a relation wherein the free fall is accelerated downwardly and arcuately at the end of the hose in swinging movement about a point where the hose progressively touches the ground.
The gun strikes the floor with a whiplash effect often resulting in damage as distinguished from being dropped only a foot or so or laid down carefully. The plastic parts thereof may be damaged or broken, and, although the gun may still be capable of dispensing liquids, its operation, the critical flow rates and ratios may be adversely affected unknowingly.